I'm curious how one could get/make some glue when in the wilderness. How did the Native Americans do it?
A fabulous source for detailed information on north american plants suitable for glue production can be obtained from Native American Ethnobotany by Daniel E. Moerman. Here are quite a few that come to mind:
And there is many more plants for complete list please get Native American Ethnobotany by Daniel E. Moerman. I might have missed some so please get the book!
Conifers are your friend here - they have a sticky sap which can be used as the base ingredient for a natural glue. It hardens relatively quickly on exposure to air and in its solid form is quite easy to store without sticking to everything, so if you have this in mind it's a good idea to collect some as you see it.
When you've got your pitch (the hardened sap from conifers) melt 5 parts of it in a pan to one part charcoal and one part finely crushed plant material. It'll become black, sticky and (as soon as heat is removed) very thick. This is great for storage because you can roll it into a ball as it cools, then heat some up when you intend to use it!
A word of warning - it's highly flammable, so watch out (especially when mixing the initial ingredients together!) Cook on hot charcoal / coals rather than an open flame to mitigate the risk somewhat of it catching fire.